20 Jun
2011
20 Jun
'11
12:01 p.m.
On 20/06/11 13:39, Andy Smith wrote:
<snipsnip details about xen-vms and memory>
I've just checked my various domU, they all run debian. Some are lenny,
some squeeze and a couple run sid. They all show the same - a certain
amount of reserved memory when booting and a "Freeing initrd memory…" a
bit later.
None of the VMs show the same amount missing, but the reserved - "initrd
freed" seems to fit very well with how much is "missing". And the more
memory that is assigned in the first place, the more is "lost". I have
one VM with 2.5GB assigned which "free -m" reports as about 60MB less
than assigned.
I don't know exactly where the memory goes, but on my 32-bit VMs
boot-time reported HIGHMEM + LOWMEM equals the amount of assigned
memory, so the "missing" memory seems to be linux-kernel overhead
somewhere. My 64-bit VMs obviously don't show HIGHMEM and LOWMEM, but
the "BIOS-provided physical RAM map:" seems to fit nicely with the
assigned memory.
- OM